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Epsom Salt for Cucumbers: When And How To Apply?

We can’t live without cucumbers, isn’t it? The vine plant belonging to the gourd family finds multiple uses in our home and kitchen. Whether it is making your favorite green salad or your DIY Face Mask, cucumbers are irreplaceable.

Farming the plant is enjoyable when the harvest is bountiful. On the flip side, nutritional deficiencies may lead to low yields.

Nutritional deficiencies could be caused by mineral imbalances in the soil or plant. Like any other plant, the cucumber thrives on soils that are well-balanced in nutrients.

Epsom salt holds the key as far as these nutrients are concerned.

It ensures your cucumber has enough Magnesium and Sulfur supply as lack of them leads to stunted growth.

In this article, we guide you on the when and how of using Epsom salt for growing the plant to ensure high yields. Let’s take a deeper dive. 


Why Use Epsom Salt For Cucumbers?

Applying Epsom salt on your cucumber plants is needful for healthy growth, greener plants, and better yields. Epsom salt is a compound composed of Magnesium and Sulfur, abbreviated as MgSO4.

You will know your soil lacks these elements when your cucumber plant begins to show Magnesium and Sulphur deficiency signs. Possible signs you want to look out for are loss of plant vigor, poor growth, and low yields.

You should only resort to Epsom salt to correct the above deficiency instead of a regular application. 

It benefits your cucumber plants because of the following reasons:

Betters Uptake Of Nitrogen

Epsom salt contains Magnesium, the element responsible for increasing the uptake of Nitrogen and Phosphorus in plants.  

Corrects Chlorosis 

The above elements improve cucumber production by correcting leaf yellowing to ensure more fruits are produced. 

Prevents Slow Growth

Cucumber plants without Epsom salt become stunted and weak. It comes in handy in ensuring they have improved strength, growth, and high yields. 

Corrects Nutrient Deficiencies 

Applying Epsom salt to cucumbers enables you to fix the damage that was brought by nutrient deficiencies. The result is dark green foliage, more bushes, and more fruit production.

Prevents Root Shock 

Epsom salt is also useful during transplanting. For example, if repotting your cucumber plant, you can mix one tablespoon in a gallon of water and water the soil to kickstart the growth again.

Fastens Seed Germination 

Epsom salt is known to give seeds a better start during germination. Apply it to the planting hole before you plant your cucumber seed. 


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The Role of Magnesium And Sulfur In Cucumber Plants And Their Deficiency Symptoms


Magnesium in cucumbers and any other plant is essential for photosynthesis, the process through which plants synthesize nutrients using solar energy.

Therefore, Magnesium is vital for normal plant growth, and its lack or deficiency could prove detrimental to the plant.

Typically, Magnesium deficiency is more severe in soils that are sandy, light, or acidic. However, clay soils under intensive production might also suffer from Magnesium deficiency. 

Symptoms Of Magnesium Deficiency In Cucumber


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  • Yellowing of older leaves. 
  • Interveinal chlorosis beginning from the leaf edges moving inwards. 
  • Light tan burns in subsequent stages, which results in tissue loss. 
  • It also leads to necrosis and leaf shriveling. 
  • The entire leaf turns yellow in severe deficiency. 

Pay attention to your cucumber plant for these symptoms, which most likely surface from mid and late into the season. 

Excessive application of Potassium to your soil is also a significant cause of Magnesium deficiency in your soils. Apply compost manure or reduce Potassium application to correct the mineral imbalance.

Your soils could also become Magnesium deficient through leaching if you live in an area with excessive rainfall. 


Sulfur in cucumbers is crucial since it helps in producing amino acids, enzymes, proteins, and vitamins.

Your cucumber’s ability to fight diseases is dependent on Sulfur. Sulfur also supports plant growth and the formation of seeds. 

Symptoms Of Sulfur Deficiency 


  • Pale green to yellow leaves. 
  • Restricted plant growth.
  • Younger leaves remain small and bend downwards. 
  • Necrotic spotting. 

When To Apply Epsom Salt To Your Cucumbers?

Add Epsom salt to your cucumbers when you spot signs of Magnesium and Sulfur deficiency. That means you need to be constantly on the lookout for any emerging symptoms.

Ideally, you should have your soils tested to determine the mineral composition and what fertilizer additions you should make to your soil.

However, many gardeners find this more technical for them. During application, you want to make sure you’re giving your cucumber the right dosage to cater to the deficiency.

Applying Epsom salts in high quantities leads to soil toxicity. 

How Frequently Should You Apply Epsom Salt?


Cucumber plants have a high water content which makes them survive the summer heat. Under normal circumstances, with no symptoms of deficiency, you can make one application during mid-season.

The fact is your cucumbers should be getting all nutrients from highly fertile soil without the need for a fertilizer boost. The recommended frequency of application when growing them in a vessel or pot is 4-5 weeks.

This is only necessary when you start noticing the deficiency symptoms. If you have planted your cucumbers in the garden, apply Epsom salt every 4-6 weeks when the symptoms emerge.

Again you shouldn’t apply Epsom salt regularly like fertilizer because it will damage your cucumber plants. Too much Epsom salt on your cucumbers causes wilting.

How To Apply Epsom Salt?

This section guides you on the various techniques you can use to apply Epsom salts to your cucumber plants. 

Applying Epsom Salt As A Solution

This is the most popular method most gardeners use. It involves adding Epsom salt to the water to form a solution.

You should pay attention to ensure you are getting the measurements right. A half tablespoon of Epsom salt is enough for half a gallon of water.

Stir the mixture well to make it effective. You want to make sure the Epsom salt dissolves fully in the water.

Pour the solution into a watering can and use it to water your cucumbers. This application should be enough to make the deficiency symptoms go away.

However, you are free to redo the application after 3-4 weeks if you still notice the symptoms around. In some cases, the symptoms may not go away even after the second application.

If this is the case, you must do a soil test to establish whether a magnesium sulfate deficiency is present or some other nutrient could be missing. 

Applying Epsom Salt As A Foliar Spray/Drench

Foliar spraying enables your plant to absorb nutrients via foliage and not the roots. It’s an effective method in boosting plant growth.

You shouldn’t stop regular watering if using the foliar spray, as your plants will still need their daily water requirements. Inconsistent watering will make your fruits taste bitter.

To get the measurements right, mix two tablespoons of Epsom salt with a gallon of water. You want to have a handheld spray bottle to use for spraying the solution to cucumbers every month.

You could also schedule the application to be bi-weekly instead of monthly. For that matter, mix one tablespoon of Epsom salt with one gallon of water.

You will need to determine whether there is an actual deficiency of Magnesium in the soil before using a foliar spray. Too much application of Epsom salt on foliage leads to leaf scorch. 

Sidedressing In Mature Cucumber Plants

Though not a popular method than the first two, side-dressing is also an easy and effective way of correcting nutritional deficiencies in your cucumber plants.

We recommend doing the application mid-season to give your plant a nutrient boost. During application, spread two tablespoons of the Epsom salt at the plant’s base. 

When Planting Your Cucumbers For The First Time

Another way of adding Epsom salt to cucumbers would be to use it during planting time.

Mix 1-2 tablespoons with the fertilizer you will use for planting, or mix one tablespoon with soil in the planting hole before you plant your cucumber.

Before using this method, you should ascertain your soils have less organic material or other vital nutrients. There would be no need to use this method if your soil is well-balanced nutrient-wise. 


By now, you should know the reasons why Epsom salt is important for your cucumbers.

Applying it to your cucumbers helps to correct the effects of Magnesium and Sulfur deficiency. Before you make the application, you should first establish whether your plants need the Epsom salt or not.

Check for possible deficiency symptoms or go for a soil test to be sure about your soil’s nutrient deficiencies. You should apply Epsom salt to your cucumbers on a need basis and not as a regular fertilizer.

The most common method of application is an Epsom salt solution. You want to get the measurements right before you do the watering. We hope you get healthy cucumbers this time round. 


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